In the production of polyurethane foams, a polyol is reacted with a polyisocyanate in the presence of a polyurethane catalyst and a blowing agent. It is well-established in the art that open-cell foams can be produced using water in the reaction mixture to provide a carbon dioxide blowing agent in situ, whereas closed-cell foams are typically produced using a chlorofluorocarbon ("CFC") blowing agent. Unfortunately, CFC blowing agents have a negative impact on the environment, and alternatives to the use of these blowing agents in the production of closed-cell foams are being sought by the polyurethanes manufacturing community.
Unfortunately, the use of amine catalysts as supplemental catalysts in combination with water to provide closed cell foams (e.g., rigid and semi-rigid foams) has heretofore not been successful to the knowledge of the present inventors, largely due to a shrinkage problem associated with the production and storage of such foams. A solution to this shrinkage problem would be highly desired by the polyurethanes manufacturing community.